We explore the Total Cost of Ownership of ultra-high efficiency modular UPS at the latest Powered On Live 2023 digital event.
Last month saw the influential industry magazine Electrical Review stage its second annual Powered On Live online seminar. The conference built on the popular ‘Powered On’ podcast and last year’s inaugural event, which brought the electrical sector together for two days of debate and discussion.
The 2023 instalment featured keynote presentations and expert panels tackling some of the hot topics facing the industry, including net zero, energy storage, cybersecurity, and power distribution.
Our Technical Services Manager Jason Yates appeared on day 1 of Powered On Live 2023, leading a session exploring the total cost of ownership of modern UPS systems.
Jason’s informative talk explored the concept of UPS efficiency and the impact of various operating modes on efficiency levels (online double conversion, ECO mode, Active ECO).
The presentation also touches on the evolution of modern UPS systems, such as from 2-level to 3-level architectures, and the subsequent improvement in efficiency.
He goes on to warn about the ‘smoke and mirrors’ of how certain manufacturers publicise an average efficiency figure and stresses that you should only use the true online efficiency ratings when comparing models.
Jason then provides an overview of Riello UPS’s latest evolution in modular UPS systems, the ultra-high efficiency Multi Power2. This new product incorporates 67 kW power modules made from state of the art silicon carbide (SiC) components, which enables it to run at up to 98.1% efficiency even in dual conversion online mode.
He outlines a practical example of how upgrading a legacy 95% efficiency data centre UPS with a new Multi Power2 could save 400,000 kWh of energy a year, the equivalent of £63,000 a year, as well as cutting annual CO2 emissions by 82 tonnes.
The session finished with a brief Q&A between Jason and Electrical Review editor Jordan O’Brien, the Powered On Live 2023 moderator.
Watch the full Powered On Live 2023 video below, which is followed by the transcript.
Powered On Live 2023 Video Transcript
I am Jason Yates, the Technical Services Manager for Riello UPS Ltd. We all know that the DC industry is one of the fastest growing and transforming industries of the last decade.
Now, we’ve seen transformations in terms of Ecosystems, Technical and Regional Requirements, System Architectures, Power Demands, Efficiency, and, of course, Total Cost of Ownership (TCO).
As a result of these transformations, the data centre industry has obviously come under the spotlight, having become very power hungry and costly to operate.
In addition to this, with 150 plus countries signing off the COP Agreement aiming to reduce the global temperatures by 2 degrees, with strong CO2 reduction targets set down for 20230 per country, basically sustainability has become one of the main challenges for humanity.
Unfortunately, we currently have growing inflation, we have geopolitical instability and the related energy crisis, and along with that we have industry supply chain difficulties.
The industry is effectively facing strong headwinds that make the whole business even more challenging.
So, the question from the Riello UPS standpoint is how can we help the DC industry become more sustainable, and at the same time minimise operating costs?
Well, we can start by looking at Power Demand and how the very latest high efficiency uninterruptible power supplies can reduce energy losses, cooling requirements, operating costs, and ultimately the CO2 emissions.
In addition to this we can look at the Total Cost of Ownership and our advancements in UPS design have helped reduce costs by using high quality, long-life components, providing user flexibility and reduced overall maintenance costs.
Double Conversion Online UPS
Let’s take a look at power demand and high efficiency double conversion UPS systems.
Basically, the measure of any UPS’s efficiency is defined as the kW input versus the kW output. The difference between the input and output is effectively lost energy which is completely wasted.
This wasted energy is mostly converted to heat, which generally needs to be removed and/or cooled, which again requires more energy.
The greater the energy loss, the lower efficiency, and the higher the costs.
Of course, every UPS manufacturer ultimately strives to achieve 100% efficiency. Sadly, however, due to current technology and of course the laws of physics, this is simply not possible.
Through advanced UPS design, however, and the latest component technology, we can get very close.
Now, before we start actually looking at that technology, I just want to explain to you a little bit about online double conversion UPS systems, how they operate, and the three typical operating modes they will be used in a data centre application.
On the screen you can see a typical diagram of an online UPS. On the left you have the input supply, and on the right there you have the load. On the bottom you have the batteries, which are obviously there to support the UPS when the mains supply fails. While at the top you have the bypass line, which is used for things like maintenance or for issues like alarms and faults and so on.
The online double conversion UPS system is so called because we take the supply from the incoming mains supply – the AC – and we convert that to DC. So that’s our first conversion. Then we take that DC and reinvert it back to AC, that’s our second conversion, hence the term dual conversion.
The beauty of the online dual conversion UPS is effectively the inverter is permanently running so permanently providing us with the clean AC waveform for the critical load, regardless of what is coming into the UPS from the mains supply.
Based on this we can say that the online UPS system provides the highest levels of protection against any network disturbances, in addition to maximum power conditioning.
The downside of online dual conversion is that because of the conversions taking place within the UPS, unfortunately it provides the lowest level of efficiency in terms of the operating modes of the UPS.
Exploring Economy Operating Modes
Another mode of operating is ECO mode. All UPS systems can do these features. ECO mode is basically the load now being powered through the bypass line, so this time the UPS isn’t performing the dual conversion process, albeit we are still maintaining the batteries so that in the event that there is a mains failure, the battery system will be available should it need to be.
One of the benefits of the ECO Mode of operation is that provides the very highest levels of efficiency, 99% plus, however, because the input is effectively connected directly to the output, there is little to no protection against instant network disturbances, therefore it provides the lowest form of protection for the critical load, so what you gain in efficiency you lose in the levels of protection.
In most UPS systems, in the event of a mains failure there would be a small break in supply to the critical load using ECO mode. You’re only talking milliseconds, but this is why it’s not a favoured mode of operation for data centre managers.
The next operating mode is a sort of mixture between ECO mode and online. It’s referred to, in our case, as Active ECO, although some manufacturers will call it Dynamic ECO or something similar.
Whatever the name, it’s very similar to ECO mode in that the load is being provided through the bypass line, so we’ve got good high efficiency. However, the actual UPS inverter is actually working in parallel with the bypass line, so it’s effectively working like an active power factor corrector or a system conditioner in terms of power factor, correcting sags, THDI, and so on.
The main benefit is again the efficiency sits somewhere between the ECO mode and online mode. However, this time you’ve got that power conditioning. The downside is that it’s still directly connected so you still have little to no protection against network disturbances, so it’s great to have but it’s not the favourite solution.
I can say with certainty that most online UPS systems will provide you the very highest levels of protection. Nearly all DC managers will operate their online UPS permanently in online mode in order to minimise any potential risks.
Avoid ‘Smoke & Mirrors’…
So when comparing UPS efficiency, we must always compare like with like, otherwise you cannot establish the true performance and any potential savings.
In my view, anything other than true online can be a bit of a gamble in terms of protection.
When stating efficiency, many UPS manufacturers will produce an average efficiency figure, which effectively is a combination of the operating modes over a set period of time, for example, 24 hours with 12 hours in online mode followed by 12 hours in ECO mode.
Now for some applications this is perfectly acceptable, but for a 24-7 data centre this isn’t acceptable as at some point you are exposing the data centre to higher levels of risk.
Unfortunately, the average efficiency is typically not a true reflection of the real-life conditions and so the figure cannot be compared to the true online figure. Basically, the average figure will typically show inflated efficiency values, which can be a little misleading.
On the other hand, high efficiency UPS can achieve extremely high efficiency levels even in online mode, so there is no need to settle for average performance.
Meet Multi Power2
Now this is not so much a sales pitch, but just to show you a typical system that is actually available in the market. This is a high efficiency modular UPS produced by Riello UPS. It’s an online double conversion system and it will provide efficiency higher than 98%
Now the system is the Multi Power2, based around a flexible, scalable, resilient, and sustainable UPS.
The main building block of this UPS system is formed around a 67 kW power module, which is then matched to three specific power cabinets. You have a 500 kW power cabinet for smaller applications; you’ve got a 1 and 1.25 MW power cabinet for larger installations; and you’ve got a 1.6 MW in frame again for larger installations.
All of these cabinets can be put in parallel to provide additional resilience to a cabinet level.
Now within all of these cabinets, the power modules form the core, so systems are populated with fully hot-swappable power modules to suit the load required at the time.
In those cabinets you’ve also got spare slots where you can fit redundant modules. In addition, the system has a fully rated bypass cabinet, and within these cabinets you’ve got full flexibility in terms of as you can see there on left is a 1 MW and 1.25 MW solution with switches, some people want the input and output switches to suit the installation.
Then on the right you’ll see the same installation where you have the system without any input switches.
So the whole point of the system is its flexible in terms of its modules. It’s scalable in that you can increase or decrease size accordingly automatically if you wish.
It’s resilient because you’ve got the redundancy. And it’s sustainable because of the technology, which I’ll come onto in a second.
Evolution Of UPS Technology
What I want to do now is actually look at how we got to this point in the marketplace in terms of UPS design. Many years ago we used to produce UPS systems by what’s referred to as a two level architecture inverter. UPS of this type would typically produce an efficiency level of around 96%.
Now don’t get me wrong, that is a good efficiency even by today’s standards, but obviously it isn’t as advanced as it is as we are now.
We then made the step move away from the two level to three level architecture, which obviously requires more components and more processing power to control.
Typically when these were first introduced, you would only really see them in large UPS systems, 100-300 kVA due to the complexity such as the number of components. It wasn’t really cost-effective to produce UPS with this architecture.
Nowadays, you will see three level architecture UPS’s as small as 10 kVA as the technology has advanced. That took us to efficiency levels of around 96.5%.
The next stage was changing the materials used in filter design, which enabled us to push the efficiency levels of the UPS up to around 97%, so we’re getting somewhere, we’re making progress.
Moving To Silicon Carbide Components
Now the biggest change that we’ve applied in recent years is the move from traditional silicon components over to silicon carbide. The use of silicon carbide is nothing new, it’s actually widely used within the electric car industry, which has helped make the technology more readily available.
We were able to move from silicon based IGBT to silicon carbide. With these devices we are able to operate UPS systems in online mode up to 98.1% efficiency.
As you can see in the table comparison on the top right, the total chip area of the silicon carbide one is about 20 of that of a typical IGBT, so it’s much smaller and the losses are much less.
Where we gain is the switching losses, you can basically see that they are around 25 of that of a traditional IGBT, so overall using silicon carbide we get a reduction of about 50% in terms of the heat generated by the device during operation.
The graph at the bottom there shows you the load levels across the components at 10, 25, 50 and 100% load, as you can see, the silicon carbide devices consistently outperforms the traditional device across all load ratings.
There are several advantages to silicon carbide. Because there are less losses we generate less heat, so we have to provide smaller heatsinks. There’s excellent thermal management, and because of this, there’s reduced component stress. We have very high power density, and we also have smaller components, which equates to a more compact overall design.
If we have a look at performance, this is a typical graph of a 500 kW system which is operating with silicon carbide components.
As you can see, the system operates with efficiency greater than 98% for a load range of about 25-50%. Generally that would be higher up. We’re still greater than 97.5% efficiency for between 15-80% load, and still further we are greater than 97% even from 10-100%, so in terms of performance, it’s extremely good.
One of the main things is this is in online mode only, this is not in ECO mode.
Benefits Of Multi Power2
So what savings could be achieved? Because there’s reduced heat output, reduced wasted heat, and reduced cooling requirements, our operating costs are going to come down.
In addition to this, because we’re using long-life components and maintenance-free capacitors, we have high mean time between failures (MTBF) and a low mean time to repair (MTTR), which reduces our overall maintenance costs.
Now it’s not just the efficiency that we’ve looked at, we’ve obviously had to consider the overall sustainability of the modules and the way we construct them.
We’ve provided a much cleaner, simplified design layout of the module itself. We provided special humidity and temperature sensors, input air temperature sensors, and added capacitor temperature monitoring too.
One of the benefits of this is that it gives us a full thermal map that helps with monitoring and predictive maintenance, so we can plan exactly how the inverter and the module is going to perform over its lifespan.
In addition, it’s fully recyclable, you’ve got reduced weight and heatsink volumes, we’ve got very granular monitoring, quick and easy assembly.
Now if we look at that in terms of costs, because we’re using long life components there’s no capacitor replacements required over the lifespan of the system. With a typical UPS this would take place around years 5-7.
In terms of maintenance, the worst case is actually the system will only require a single fan replacement in its lifetime, around year 8. However, the operational conditions could mean that a fan replacement may be completely avoided for the 15 year life of the product.
The controllers carefully monitor all consumable components, providing a comprehensive self-diagnosis system, in addition to this there’s also intelligent and advanced thermal monitoring.
So how does this affect the total cost of ownership of our UPS? Well if we look on the graph, you can see the greatest portion is energy costs and the next greatest portion is operations and maintenance, which is why we’ve focused on these two areas.
If we deploy a 98% efficiency UPS in place of a 95% UPS, which don’t get me wrong is a well-performing UPS in its own right, and based on 1.25 MW UPS with a 1 MW load, you can see we could make savings of 400,000 kWh per year.
This equates to more than £63,000 a year, nearly £1 million over 15 years. In one year we would save 82 tonnes of CO2, and over 15 years over 1,230.
Based on maintenance costs, a typical site could save in excess of £80,000-120,000 over a 15 year period, and because of the advanced diagnostics, it significantly reduces engineers’ time on site, thus reducing costs through resource requirements.
True hot-swappability means it’s easy and quick to repair and a low mean time to repair of less than 30 minutes ensures that any maintenance prices are kept to a minimum.
To summarise, always compare like with like, always make sure you’re comparing an online UPS with an online UPS, not an average figure.
So that’s the Multi Power2 UPS, designed and manufactured by Riello UPS in Italy.
I’d like to thank you for listening today, and if you have any questions, then go for it.
A short question and answer session followed Jason’s presentation, with Electrical Review editor Jordan O’Brien posing the questions.
Jordan: one you probably hear all the time, but obviously one of the large costs with buying a UPS is the initial outlay, so how can companies reduce that up front cost? Is it specifying the system for the future or by right-sizing it now?
Jason: One thing we do, we revisit data centres that have been you know installed many years ago, and I know there are many times where we see them completely underutilised, and it’s a shame because you know what they plan to install from day one is never really the target.
The beauty of these modular systems, yes the CAPEX at the beginning can be significantly high, but you’re going to get that payback much sooner along the OPEX curve.
With a scalable solution, especially in this case, some people will install them and they will utilise a fully automatic system whereby they will fully populate with all of the hardware and then what they will do as the load on their data centre increases, decreases or changes, the system will automatically bring online only the number of modules needed to power the load and maintain the redundancy levels.
The main thing in terms of the costs with a system like this, it’s only the module that’s silicon carbide, the cabinet is the same. It obviously depends on the size of the system, but the cost is going to be somewhere between 7-12%, which is not that great when you look at the big numbers.
Jordan: Michael Cunningham asks on the subject of paybacks, do you have any examples of paybacks that have been achieved through installation of the high efficiency systems?
Jason: Yes, we did one recently where the system was in operation and it paid for itself from a hardware perspective just before year 6, I think, which was obviously very good. You’ve also got to consider payback in terms of batteries and things like that too.
But purely from a hardware perspective, what we try to do is get more real-life because there’s so many variables in terms of payback, you’ve got the cost of electricity where people are paying so many different values, climate control levels, reactive power charges, all these additional things to consider.
Jordan: Someone called Charles Goldtry asks that the efficiency is verified but who carries this out for the UPS sector?
Jason: It depends, you can go for the likes of UV, who would do the certification, we had this one independently verified by KIWA, I think with those modules we operated at 230 volts to obtain the 98.1% but if we operated them at 240 volts we could have actually achieve 98.3%, but that’s not been independently verified.
Jordan: I’ve got one more question, which is another way you can reduce the TCO of any UPS is through maintenance. What are the top tips you’d share to ensure you get longevity out of your UPS?
Jason: The key one is to stick to the manufacturer’s guidance, otherwise it can become very costly if something goes wrong. Components within a UPS, like any components, have a finite lifespan, the likes of capacitors, fans, etc.